The purpose of the Scientific Core is to facilitate scientific research activities of the individual projects of the Program Project. The Scientific Core coordinates centralized purchasing of general laboratory supplies and certain molecular biology and tissue supplies. By grouping orders from individual projects and this Core, larger orders are accumulated to economize on such items as serum, media, culture dishes, enzymes, labeled DNA precursors, and pipette tips, all of which can be purchased much more cheaply in large quantity or in bulk. Shipping charges are also greatly reduced by combining purchases of enzymes and radioactively labeled compounds. The Core oversees distribution of these supplies to each project and charges each project for the costs of these supplies. The Scientific Core also facilitates the Program by supporting activities that use molecular biology techniques and tissue culture. Centralization of certain operations benefits all projects and improves quality control of molecular biology and tissue culture activities. By pooling these activities, the Core serves all projects. It helps to economize on cost and to increase uniformity of characteristics of molecular biology products and cells used in current projects. The Core provides more stringent control of quality of molecular biology reagents and procedures. The Core obtains plasmids carrying genes that are valuable to the whole Program. Plasmids are grown an samples are provided to investigators and the excess is put in storage in our freezers. Molecular reagents are carefully characterized and they are made available to projects as necessary. The Core staff prepares probes that are needed in several projects so the same reagents are used in common between projects. It is a goal for the Core to become more responsible for preparation and testing of routinely used media and tissue culture fluids. The Core will also maintain stocks of cell lines, it will oversee cell storage and retrieval, and it will test for mycoplasma. It will also establish new human primary cell cultures as needed and will coordinate testing of tumorigenicity of cells in nude or SCIDS mice as needed by the Program.